Working of TWS Earbuds, Bluetooth Headphones, Earphones, and Headsets. A Scientific View!

Bluetooth or wireless technology is not a new entry in the tech world. But it has revolutionised the concept of headphones even among the common people. It is quite natural for a normal person to wonder how a Bluetooth headset works?


The working of a wired earphone is not a “Nolan’s thing” because there we have a cable to carry the audio signal. But here, we don’t have any such cable to take the current that carries audio signals from a mobile phone to a headset. How are Bluetooth devices connected to each other and form a Piconet for transferring data without a cable?

Here we clear all your doubts about how does a Bluetooth headset work.

What is a Wireless Headphone?

Before we take you deep into the science behind wireless earphones, we believe it is essential to tell what are Bluetooth headsets. They are a kind of headset without any cables to connect your audio source and headphone. Here the signal transfer occurs through radio or infrared waves instead of wires. Whether you are using True Wireless Stereo (TWS) earbuds, wireless headphones, headset, or earphone, the working principle is the same. 

We have already discussed the types of headsets and neckband and True Wireless Stereo earbuds are two predominant Bluetooth models. You can use them to connect with different devices like smartphones, smart TV, gaming console, laptop, and other electronic items.

How a Bluetooth Headset works?

The working of wireless headphones is similar to wired types except for the bridge between audio source and headset. 


When you activate the Bluetooth, it creates a piconet, and a communication channel is established; we call it pairing. Now they can transfer information between them. 

When you want to hear a song through a paired wireless headset first, the smartphone takes the audio information from the flash storage chip. Then it is given to the phone’s storage. There it will be converted into digital signals as corresponding numbers. The length and complexity of the digital depend on the audio details. 

The smartphone then sorts and arrange them into digital packets and send them to the headphone through the radio waves. This process will typically be based on the Bluetooth specification.

Then the headphone receiver arranges and sorts it back to the initial numbers. It will then be given to the audio codeca computer program that decompresses digital audio data into a corresponding audio file.

The audio codec converts it into an analogue waveform because headphone parts like coil and magnet can not read the digital data directly.

Then this waveform fed into the voice coil, and it moves up and down based on the signal. Then as we all know, this vibration moves the air around it and produces the corresponding audio output. This is the Bluetooth headset working principle.

Bluetooth Version

Majority of the wireless earphones and TWS earbuds work on Bluetooth version 4 or the latest version 5. These two versions ensures approximately 10 meters of drop-free and crystal clear communication.

Their range is unaffected by wind and other small hindrances such as partitions.

Wireless technology uses radio or infrared frequency waves to transfer sound signals. But the Bluetooth feature depends mainly on radio waves from 2.4 GHz to 2.48 GHz, which means that they are moving at a speed of 2.4 to 2.48 billion waves per second. 

Even though that handles such a massive amount of data, the power consumption is too too low in the range of 1 milliwatt or so.

The two main things that are mandatory to establish wireless connectivity are a transmitter and a receiver. The audio source such as mobile phones, smart TVs, etc., contains a transmitter with an inbuilt chip for pairing with nearby devices with Bluetooth technology.

But that is not enough; headphones need something to receive the audio signals. The radio receivers receive them and act as a transducer. You may know transducers as the devices that convert energy from one form to another. They retrieve sound from the signal.

You have to press the power button on the wireless device to activate the Bluetooth mode. Then only it can pair with a nearby device, and that’s why your device needs an external power source like a Li-ion battery.

There are two types one is Bluetooth Low Energy (BLE) and another is Bluetooth Enhanced Data Rate (EDR). Studies show that BLE is more efficient in the transfer of data.

What is an Audio Codec?

It is the abbreviation of coding and decoding. Even though it can be software or hardware, wireless bluetooth exclusively uses specialized software.

Based on the requirement, it compresses or decompresses data; in other words, it converts data from one form to another. Here, the audio codec converts digital audio data into voice coil-compatible analog waveforms (or ~sinusoidal waveforms.

In simple terms, it enables Digital to Analogue Conversion (DAC). 

It can also work in the inverse direction, i.e., ADC.

Wireless Headphones and Health Concerns

Two factors we consider most while using electronic devices are comfort and health problems. In addition to hearing safety, Bluetooth device users also doubtful about radiation hazards. 


In a positive sense, the hazardous non-ionizing radiation from a wireless headset is far less than that from a smartphone. On the other hand, it is quite sorry to say that health issues associated with Bluetooth devices are yet to study deeply.

The approach from Federal Communication Commission implies they are safe.

Final Thoughts

We hope this article helps you to understand how a Bluetooth headset works. Most of the headphones have a frequency response of 20 Hz to 20 kHz because this is the audible limit of a human ear.

  1. How does Bluetooth work without wifi?

    As we discussed earlier, Bluetooth uses radio waves from the transmission of audio signals from an audio source such as a mobile phone to headphones. It does not require any cellular data, so no internet or wifi.
    Wifi needs when you want to connect your device to the internet to gather some data from an external source. One of the main advantages of Bluetooth technology is it doesn't need a working internet connection; it is completely free.

  2. How to turn on Bluetooth headset?

    Depending on your model, it varies. Sometimes you have a power button, and you have to make a long press to turn it on. In some other devices with the smart touch feature, you just touch for 2-3 seconds on the power symbol to activate the Bluetooth mode.
    Then a green light on the headphone will glow, and you can assure that your headphone's Bluetooth is turned on and ready to pair.

  3. Why my Bluetooth headset is not working, or why isn't my Bluetooth headset working?

    Suppose you wore your Bluetooth earphone and try to connect and fails first thing you have to check is its charge. If it does not have a minimum charge, you have to charge and try to start.
    If it is still not working, make sure that the audio source is within the Bluetooth range. If it is beyond the limit, keep both the devices within the range.
    If it has enough charge and within the range and fails to connect, you try to remove it and connect it back and restart both the device. It will definitely work. This is how to get a Bluetooth headset working.
    Otherwise, really sorry to say, your device has got some serious problem and reach out to a service centre immediately.

Sanil VS is a Chemical Engineer by Profession and he loves to write and review gadgets on his free times.

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